R16.1 Feature request: coreconverter.exe return code for error

Please make coreconverter.exe return code be non=zero in event of error.

Currently the lack of a return code indicating error makes CoreConverter.exe not properly usable on many environment. It is standard for command-line programs to indicate errors in the return code. Since it doesn't to that, CoreConverter.exe doesn't fit properly in everything from MAKE to PowerShell.